Light-emitting device

Abstract

The objective is to improve the heat dissipation of the light-emitting device. [Solution] A first conductive member 10, a second conductive member 20 spaced apart from the first conductive member in a first direction, a first joining member 30 positioned on the upper surface of the first conductive member, a second joining member 40 positioned on the upper surface of the second conductive member, and a light-emitting element 50 positioned on the first and second joining members and spanning the first and second conductive members, having a light-emitting portion 51 and a first electrode 52 and a second electrode 53 positioned on the lower surface of the light-emitting portion and spaced apart from each other in a first direction, wherein the first electrode has a first portion 521 in contact with the light-emitting portion and the first joining member, and a second portion located on the second electrode side of the first portion and having a lower surface located above the lower surface of the first portion, wherein in cross-sectional view, the thickness of the second portion of the first electrode is greater than the thickness of the light-emitting portion, and the first distance in the first direction between the second portion of the first electrode and the second electrode is smaller than the second distance in the first direction between the first conductive member and the second conductive member.

Description

[Technical Field]

[0001] This disclosure relates to a light-emitting device. [Background technology]

[0002] Patent Document 1 discloses an electrical element mounting structure comprising a first lead frame and a second lead frame that are spaced apart and facing each other, and an electrical element mounted on one surface of the first lead frame and the second lead frame with a conductive adhesive, straddling the space between the first lead frame and the second lead frame. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2003-86453 [Overview of the project] [Problems that the invention aims to solve]

[0004] This disclosure aims to improve the heat dissipation performance of a light-emitting device. [Means for solving the problem]

[0005] A light-emitting device according to one embodiment of the present disclosure includes: a first conductive member; a second conductive member spaced apart from the first conductive member in a first direction; a first bonding member disposed on the upper surface of the first conductive member; a second bonding member disposed on the upper surface of the second conductive member; a light-emitting element disposed on the first bonding member and the second bonding member and spanning the first conductive member and the second conductive member, having a light-emitting portion and a first electrode and a second electrode disposed on the lower surface of the light-emitting portion and spaced apart from each other in a first direction; and the first conductive member, the second conductive member, and the front The device comprises a first bonding member, a second bonding member, and a light-reflective covering member covering the light-emitting element, wherein the first electrode has a first portion in contact with the light-emitting part and the first bonding member, and a second portion located on the second electrode side of the first portion and in contact with the light-emitting part, the second portion having a lower surface located above the lower surface of the first portion, wherein in cross-sectional view, the thickness of the second portion of the first electrode is greater than the thickness of the light-emitting part, and the first distance in the first direction between the second portion of the first electrode and the second electrode is smaller than the second distance in the first direction between the first conductive member and the second conductive member. [Effects of the Invention]

[0006] According to one embodiment of the present disclosure, the heat dissipation performance of the light-emitting device can be improved. [Brief explanation of the drawing]

[0007] [Figure 1] This is a schematic top view showing a light-emitting device according to an embodiment. [Figure 2] This is a schematic cross-sectional view showing the light-emitting device along line II-II in Figure 1. [Figure 3] This is a partially cross-sectional view of the light-emitting device, showing an enlarged view of region III as depicted in Figure 2. [Figure 4] This is a partial cross-sectional view of a light-emitting device showing another example of the configuration of the first joining member provided by the light-emitting device. [Figure 5] Figure 2 is a partially cross-sectional view of the light-emitting device, showing an enlarged view of region V. [Figure 6] This is a schematic top view showing a light-emitting device according to a modified embodiment. [Figure 7] Figure 6 is a schematic cross-sectional view showing the light-emitting device along line VII-VII. [Modes for carrying out the invention]

[0008] The light-emitting device according to the embodiments of this disclosure will be described in detail below with reference to the drawings. However, the embodiments shown below are illustrative of light-emitting devices that embody the technical concept of the embodiments and are not limited thereto. Furthermore, the dimensions, materials, shapes, relative arrangements, etc. of the components described in the embodiments are not intended to limit the scope of this disclosure to those described therein, unless otherwise specified, but are merely illustrative examples. Note that the size, positional relationships, etc. of the members shown in each drawing may be exaggerated for clarity of explanation. Also, in the following description, the same name and reference numerals indicate the same or similar members, and detailed explanations will be omitted as appropriate. In some cases, end view diagrams showing only the cross-section may be used as cross-sectional views.

[0009] In the diagrams shown below, directions may be indicated by the X, Y, and Z axes. The X, Y, and Z axes are mutually orthogonal. In this specification, the X-axis direction may be referred to as "first direction X," the Y-axis direction as "second direction Y," and the Z-axis direction as "third direction Z." In the X-axis direction, the direction in which the arrow points is denoted as the +X side, and the opposite direction as the -X side. In the Y-axis direction, the direction in which the arrow points is denoted as the +Y side, and the opposite direction as the -Y side. In the Z-axis direction, the direction in which the arrow points is denoted as upward or the +Z side, and the opposite direction as downward or the -Z side.

[0010] Furthermore, in the terminology of the embodiments, "top view" refers to viewing the object from the +Z side. However, these do not restrict the orientation of the light-emitting device when it is in use, and the orientation of the light-emitting device is arbitrary. Also, in the embodiments, the +Z side surface (i.e., the surface of the object when viewed from the +Z side) is referred to as the "top surface," and the -Z side surface (i.e., the surface of the object when viewed from the -Z side) is referred to as the "bottom surface."

[0011] Also, in the present disclosure, unless otherwise specified, polygons such as rectangles include shapes with chamfers or other processing applied to the corners of the polygon, and are also referred to as polygons. Also, not limited to the corners (i.e., the ends of the sides), shapes with processing applied to the middle part of the sides are likewise referred to as polygons. That is, shapes with partial processing while leaving the polygon as a base are included in the interpretation of "polygon" described in the present disclosure.

[0012] Also, "covering" includes not only cases of direct contact but also cases of indirectly covering, for example, through other members. Also, "arranging" includes not only cases of direct contact but also cases of indirectly arranging, for example, through other members.

[0013] [Embodiment] Referring to FIGS. 1 to 5, an example of the configuration of the light-emitting device 1 according to the embodiment will be described. FIG. 1 is a top view schematically showing the light-emitting device 1 according to the embodiment. FIG. 2 is a cross-sectional view schematically showing the light-emitting device 1 taken along line II-II of FIG. 1. FIG. 3 is a partial cross-sectional view of the light-emitting device 1 with the region III shown in FIG. 2 enlarged. FIG. 4 is a partial cross-sectional view of the light-emitting device 1 showing another configuration example of the first joining member 30 included in the light-emitting device 1. FIG. 5 is a partial cross-sectional view of the light-emitting device 1 with the region V shown in FIG. 2 enlarged.

[0014] The light-emitting device 1 shown in FIGS. 1 and 2 includes a first conductive member 10, a second conductive member 20, a first joining member 30, a second joining member 40, a light-emitting element 50, and a covering member 60. In the example shown in FIGS. 1 and 2, the light-emitting device 1 further includes a translucent member 70 and a light guide member 80.

[0015] In the example shown in FIG. 1, the light-emitting device 1 has a rectangular shape in a top view. In the examples shown in FIGS. 1 and 2, the light-emitting device 1 includes two conductive members, i.e., a first conductive member 10 and a second conductive member 20. However, the number of conductive members included in the light-emitting device 1 may be three or more. Also, in the examples shown in FIGS. 1 and 2, the first conductive member 10 is disposed on the -X side, and the second conductive member 20 is disposed on the +X side. However, the positional relationship between the first conductive member 10 and the second conductive member 20 in the first direction X may be reversed.

[0016] As shown in FIG. 2, the light-emitting element 50 has a light-emitting portion 51, and a first electrode 52 and a second electrode 53 that are disposed on the lower surface 51b of the light-emitting portion 51 and are separated from each other in the first direction X. The first electrode 52 has a first portion 521 that contacts the light-emitting portion 51 and the first bonding member 30, and a second portion 522 that is located on the second electrode 53 side of the first portion 521 and contacts the light-emitting portion 51. The lower surface 522b of the second portion 522 is located above the lower surface 521b of the first portion 521.

[0017] As shown in FIG. 5, in a cross-sectional view, the thickness 522H of the second portion 522 of the first electrode 52 is thicker than the thickness 51H of the light-emitting portion 51. Also, in a cross-sectional view, a first distance W1 in the first direction X between the second portion 522 of the first electrode 52 and the second electrode 53 is smaller than a second distance W2 in the first direction X between the first conductive member 10 and the second conductive member 20. According to the light-emitting device 1, the possibility of a short circuit occurring between the first conductive member 10 and the second conductive member 20 can be reduced, and the heat generated in the light-emitting portion 51 can be efficiently released to the first conductive member 10 and the second conductive member 20 side through the second portion 522.

[0018] In the region on the lower surface of the light-emitting section 51 that is in contact with the first electrode 52 and the second electrode 53, heat generated in the light-emitting section 51 is easily dissipated by transferring it through the first electrode 52 and the second electrode 53. In contrast, in the region on the lower surface of the light-emitting section 51 between the first electrode 52 and the second electrode 53, heat generated in the light-emitting section 51 is less easily dissipated by transferring it through the first electrode 52 and the second electrode 53. Therefore, by making the first distance W1 in the first direction X between the second portion 522 of the first electrode 52 and the second electrode 53 smaller than the second distance W2 in the first direction X between the first conductive member 10 and the second conductive member 20, the region on the lower surface of the light-emitting section 51 where heat generated in the light-emitting section 51 is less easily dissipated can be reduced, thereby improving the heat dissipation performance of the light-emitting device 1.

[0019] In this specification, "thickness" refers to the distance in the third direction Z. In this specification, "first distance W1" refers to the shortest distance between the second portion 522 and the second electrode 53 in the example shown in Figure 5. In the example shown in Figure 5, the shortest distance between the second inner surface 522c of the second portion 522 and the fourth inner surface 532c of the fourth portion 532 of the second electrode 53 corresponds to the first distance W1. In the example shown in Figure 5, "second distance W2" refers to the shortest distance between the first conductive member 10 and the second conductive member 20. In the example shown in Figure 5, the distance between the inner ends of the upper surface 11 of the first conductive member 10 and the upper surface 21 of the second conductive member 20 corresponds to the second distance W2.

[0020] The following describes each component that makes up the light-emitting device 1.

[0021] <First conductive member 10, second conductive member 20> The first conductive member 10 and the second conductive member 20 are conductive members for supplying power to the light-emitting element 50. In the examples shown in Figures 1 and 2, the first conductive member 10 and the second conductive member 20 are plate-shaped members patterned into a predetermined shape. The upper surfaces of the first conductive member 10 and the second conductive member 20 are flat surfaces and are parallel to the first direction X and the second direction Y.

[0022] Each of the first conductive member 10 and the second conductive member 20 may have a substrate and a plating layer disposed on the surface of the substrate. Examples of materials constituting the substrate include copper (Cu), aluminum (Al), silver (Ag), gold (Au), zinc (Zn), chromium (Cr), tungsten (W), cobalt (Co), nickel (Ni), rhodium (Rh), ruthenium (Ru), and alloys thereof. The substrate may also contain trace elements such as nonmetals like silicon (Si) and phosphorus (P). The substrate may have a single-layer structure or a laminated structure composed of these metals or alloys.

[0023] The plating layer is preferably composed of a material with a higher reflectivity than the substrate. Examples of materials that make up the plating layer include Ni, Ag, Au, platinum (Pt), palladium (Pd), Al, W, molybdenum (Mo), Ru, and Rh. The plating layer may be a single-layer structure or a multilayer structure composed of these metals. Examples of multilayer plating layers include Ni / Pd / Au (i.e., a plating layer laminated in the order of Ni, Pd, and Au from the substrate side), Ni / Pt / Au (i.e., a plating layer laminated in the order of Ni, Pt, and Au from the substrate side), and Ni / Au / Ag (i.e., a plating layer laminated in the order of Ni, Au, and Ag from the substrate side).

[0024] As shown in Figure 2, the first conductive member 10 has an upper surface 11, a lower surface 12 located opposite the upper surface 11 in the third direction Z, and a plurality of side surfaces located between the upper surface 11 and the lower surface 12 in the third direction Z. Of the plurality of side surfaces, the side surface located on the second conductive member 20 side is the first side surface 13, and the side surface located opposite the first side surface 13 in the first direction X is the second side surface 14.

[0025] In the example shown in Figure 2, the first side surface 13 has two curved surfaces that are recessed to the -X side. The point where the curved surface located on the -Z side is most recessed to the -X side is located further to the -X side than the point where the curved surface located on the +Z side is most recessed to the -X side. This makes it possible to increase the distance in the first direction X between the lower surface 12 of the first conductive member 10 and the lower surface 22 of the second conductive member 20. As a result, when mounting the light-emitting device 1 on a mounting substrate using adhesive members, the adhesive members placed on the first conductive member 10 and the second conductive member 20 are less likely to come into contact with each other, thus reducing the possibility of short circuits. Note that the first side surface 13 is not limited to having two curved surfaces. For example, the first side surface 13 may consist of a single surface, such as a vertical surface perpendicular to the lower surface 12, or an inclined surface inclined to the lower surface 12. Furthermore, the first side surface 13 may be composed of three surfaces, including a first surface located on the +Z side of the first side surface 13 and perpendicular or inclined with respect to the upper surface 11, a second surface located on the -Z side of the first side surface 13 and perpendicular or inclined with respect to the lower surface 12, and a third surface connecting the first surface and the second surface.

[0026] The second conductive member 20 is separated from the first conductive member 10 in the first direction X. Like the first conductive member 10, the second conductive member 20 may have an upper surface 21, a lower surface 22, and a plurality of side surfaces located between the upper surface 21 and the lower surface 22 in the third direction Z. Of the plurality of side surfaces, the side located on the side of the first conductive member 10 and facing the first side surface 13 of the first conductive member 10 is the third side surface 23, and the side located on the opposite side of the third side surface 23 in the first direction X is the fourth side surface 24. The other configurations of the second conductive member 20 may be the same as those of the first conductive member 10. Therefore, a description of the other configurations of the second conductive member 20 is omitted.

[0027] <First joining member 30, second joining member 40> The first bonding member 30 joins the first conductive member 10 and the first electrode 52 of the light-emitting element 50. By joining the first conductive member 10 and the first electrode 52 via the first bonding member 30, the first conductive member 10 and the first electrode 52 are electrically connected.

[0028] The first bonding member 30 is positioned on the upper surface 11 of the first conductive member 10. In the example shown in Figure 2, the first electrode 52 of the light-emitting element 50 has a first portion 521 and a second portion 522 located on the second electrode 53 side of the first portion 521. The first portion 521 has a lower surface 521b, a first inner surface 521c, and an outer surface 521d. The second portion 522 has a lower surface 522b. In this case, the first bonding member 30 covers the lower surface 521b and the outer surface 521d of the first portion 521 of the first electrode 52. In other words, the first bonding member 30 has an inner portion 31 located between the first conductive member 10 and the first portion 521 in the third direction Z, and an outer portion 32 that covers the outer surface 521d of the first portion 521. The boundary line between the inner portion 31 and the outer portion 32 is a virtual straight line 30i extending downward from the lower end of the outer surface 521d of the first portion 521 of the first electrode 52 shown in Figure 3.

[0029] Furthermore, in the example shown in Figure 2, the first joining member 30 does not cover the first inner surface 521c of the first portion 521 and the lower surface 522b of the second portion 522. In other words, the first inner surface 521c of the first portion 521 and the lower surface 522b of the second portion 522 are exposed from the first joining member 30. This reduces the possibility of the first joining member 30 contacting the second electrode 53 and / or the second conductive member 20 via the second portion 522 of the first electrode 52, thereby reducing the possibility of a short circuit. Also, from the viewpoint of reducing the possibility of a short circuit between the first electrode 52 and the second electrode 53, it is preferable that the first joining member 30 does not cover the second inner surface 522c of the second portion 522 that is located on the second electrode 53 side.

[0030] In the example shown in Figure 3, the outer portion 32 of the first joining member 30 is in contact with the lower surface 51b of the light-emitting portion 51 of the light-emitting element 50. This further improves the heat dissipation of the light-emitting device 1. However, the outer portion 32 of the first joining member 30 is not limited to being in contact with the lower surface 51b of the light-emitting portion 51 of the light-emitting element 50; it does not have to be in contact with the lower surface 51b of the light-emitting portion 51. If the outer portion 32 of the first joining member 30 is not in contact with the lower surface 51b of the light-emitting portion 51, the stress applied from the first joining member 30 to the light-emitting portion 51 can be reduced, thereby reducing the possibility of damage to the light-emitting portion 51.

[0031] In the example shown in Figure 3, the distance 32W1 in the first direction X in the region of the outer portion 32 on the light-emitting part 51 side is the same as the distance 32W2 in the first direction X in the region of the outer portion 32 on the first conductive member 10 side. For example, the outer surface 321 of the outer portion 32 is a vertical surface perpendicular to the upper surface of the first conductive member 10. This reduces the stress applied from the first joining member 30 to the light-emitting part 51, compared to the case where the outer surface 321 of the outer portion 32 is inclined with respect to the upper surface of the first conductive member 10, and thus reduces the possibility of damage to the light-emitting part 51. This is because, when comparing the case where the outer surface 321 of the outer portion 32 is a vertical surface perpendicular to the upper surface of the first conductive member 10 with the case where the outer surface 321 of the outer portion 32 is inclined with respect to the upper surface of the first conductive member 10, under the condition that the contact area between the outer portion 32 and the light-emitting part 51 is the same in both cases, the volume of the outer portion 32 is smaller when the outer surface 321 of the outer portion 32 is a vertical surface.

[0032] In contrast, in the example shown in Figure 4, the distance 32W3 in the first direction X in the region of the outer portion 32A on the light-emitting portion 51 side is smaller than the distance 32W4 in the first direction X in the region of the outer portion 32A on the first conductive member 10 side. For example, the outer surface 321A of the outer portion 32A is inclined with respect to the upper surface of the first conductive member 10. Since the heat generated in the light-emitting portion 51 spreads to the -X side and then propagates to the -Z side, if the outer surface 321A of the outer portion 32A is inclined with respect to the upper surface of the first conductive member 10 of the first electrode 52, the heat generated in the light-emitting portion 51 can be efficiently dissipated to the first conductive member 10 side.

[0033] When the outer surface 321A of the outer portion 32A is inclined with respect to the upper surface of the first conductive member 10, in the example shown in Figure 4, it is composed of a single inclined surface. However, it is not limited to this, and the outer surface 321A of the outer portion 32A may be composed of a first vertical surface perpendicular to the upper surface of the first conductive member 10 in the region of the outer portion 32A on the first conductive member 10 side, a second vertical surface perpendicular to the lower surface of the light-emitting portion 51 in the region of the outer portion 32A on the light-emitting portion 51 side, and an inclined surface connecting the first vertical surface and the second vertical surface.

[0034] Examples of materials constituting the first joining member 30 include alloys such as Au-Sn, Sn-Ag-Cu, Sn-Cu, Sn-Sb, Sn-Bi, Sn-In, Sn-Pb, and Ni-Sn.

[0035] As shown in Figure 2, the second joining member 40 joins the second conductive member 20 and the second electrode 53 of the light-emitting element 50. The second conductive member 20 and the second electrode 53 are electrically connected by being joined via the second joining member 40. The second joining member 40 is also positioned on the upper surface 21 of the second conductive member 20. The second joining member 40 can have the same configuration as the first joining member 30, except that it is positioned on the upper surface 21 of the second conductive member 20 and is in contact with the second electrode 53. Therefore, a description of the other configurations of the second joining member 40 is omitted.

[0036] <50 light-emitting elements> The light-emitting element 50 is a semiconductor element that emits light on its own when a voltage is applied. An example of the light-emitting element 50 is an LED (Light Emitting Diode) chip. The light-emitting element 50 is arranged on the first bonding member 30 and the second bonding member 40 and straddles the first conductive member 10 and the second conductive member 20. The light-emitting element 50 also has a light-emitting portion 51 and a first electrode 52 and a second electrode 53 which have opposite polarities.

[0037] As shown in Figure 2, the first electrode 52 is positioned between the light-emitting unit 51 and the first conductive member 10 in the third direction Z. The second electrode 53 is positioned between the light-emitting unit 51 and the second conductive member 20 in the third direction Z.

[0038] In the example shown in Figure 2, the light-emitting element 50 may further include an element substrate 54 disposed on the light-emitting part 51. The element substrate 54 is translucent. Hereinafter, "translucent" means having a transmittance of at least 60%, preferably 80%, to the light emitted by the light-emitting element 50. Examples of materials constituting the element substrate 54 include sapphire, spinel, glass, aluminum nitride, and silicon carbide. However, the light-emitting element 50 does not necessarily have to have an element substrate 54.

[0039] The light-emitting section 51 may have an upper surface 51a, a lower surface 51b, and a plurality of side surfaces located between the upper surface 51a and the lower surface 51b in the third direction Z.

[0040] The light-emitting section 51 includes a semiconductor laminate. The light-emitting section 51 may further include, for example, two conductive layers disposed on the lower surface of the semiconductor laminate. The two conductive layers are spaced apart in a first direction X. One of the two conductive layers is disposed between the semiconductor laminate and the first electrode 52. The other of the two conductive layers is disposed between the semiconductor laminate and the second electrode 53.

[0041] The semiconductor stack comprises a first semiconductor layer, an active layer, and a second semiconductor layer. The first semiconductor layer, the active layer, and the second semiconductor layer are stacked in a third direction Z. The first semiconductor layer and the second semiconductor layer have different conductivity types. For example, if the first semiconductor layer is an n-type semiconductor layer, the second semiconductor layer is a p-type semiconductor layer. If the first semiconductor layer is a p-type semiconductor layer, the second semiconductor layer is an n-type semiconductor layer. One of the first and second semiconductor layers is electrically connected to the first electrode 52. The other of the first and second semiconductor layers is electrically connected to the second electrode 53. The active layer may have a single quantum well (SQW) structure or a multi-quantum well (MQW) structure including multiple well layers.

[0042] Each of the first semiconductor layer, the active layer, and the second semiconductor layer is, for example, a semiconductor layer made of a nitride semiconductor. Nitride semiconductors are made of In x Al y Ga 1-x-y The semiconductor comprises all compositions in which the composition ratios x and y are varied within their respective ranges in the chemical formula N (0 ≤ x, 0 ≤ y, x + y ≤ 1). The emission peak wavelength of the active layer can be appropriately selected depending on the purpose. The active layer is configured to emit, for example, visible light or ultraviolet light.

[0043] When a structure including a first semiconductor layer, an active layer, and a second semiconductor layer is considered as a single laminate, the light-emitting section 51 may comprise multiple laminates. In this case, for example, the multiple laminates may be stacked sequentially in the third direction Z. The multiple active layers comprising each of the multiple laminates may include well layers with different emission peak wavelengths, or they may include well layers with the same emission peak wavelength.

[0044] The combination of emission peak wavelengths of multiple laminates can be selected as appropriate. For example, when a semiconductor laminate comprises two laminates, possible combinations of light emitted from the active layers of each laminate include blue light and blue light, green light and green light, red light and red light, ultraviolet light and ultraviolet light, ultraviolet light and blue light, blue light and green light, blue light and red light, or green light and red light. For example, when a semiconductor laminate comprises three laminates, possible combinations of light emitted from the active layers of each laminate include blue light, green light, and red light.

[0045] The first electrode 52 has a first portion 521 and a second portion 522 located on the second electrode 53 side of the first portion 521. In the example shown in Figure 5, the first portion 521 and the second portion 522 are continuous. Also, the thickness 521H of the first portion 521 is thicker than the thickness 522H of the second portion 522.

[0046] As shown in Figure 2, the first portion 521 has an upper surface 521a that is in contact with the light-emitting portion 51, a lower surface 521b that is in contact with the first joining member 30, and a first inner surface 521c and an outer surface 521d located between the upper surface 521a and the lower surface 521b in the third direction Z.

[0047] In the example shown in Figure 2, the upper surface 521a and lower surface 521b of the first portion 521 are flat surfaces parallel to the first direction X and the second direction Y. The first inner surface 521c is located in the third direction Z between the lower surface 521b of the first portion 521 and the lower surface 522b of the second portion 522. In the example shown in Figure 2, the first inner surface 521c is a vertical surface perpendicular to the lower surface 521b of the first portion 521. However, the first inner surface 521c may be, for example, an inclined surface that is inclined with respect to the lower surface 521b of the first portion 521. The inclined surface may be a straight line or a curve in cross-sectional view. If the first inner surface 521c is an inclined surface, the angle between the lower surface 521b of the first portion 521 and the first inner surface 521c is preferably 90 degrees or more. This allows the heat generated in the light-emitting section 51 that has been transferred to the second section 522 to be efficiently dissipated to the first section 521. As a result, the heat dissipation performance of the light-emitting device 1 can be further improved.

[0048] In the example shown in Figure 5, the third distance W3 in the first direction X between the first inner surface 521c of the first portion 521 and the second electrode 53 is greater than the second distance W2 in the first direction X between the first conductive member 10 and the second conductive member 20. Hereinafter, in this specification, "third distance W3" refers to the shortest distance between the first inner surface 521c of the first portion 521 and the second electrode 53 in the example shown in Figure 5. In the example shown in Figure 5, in a cross-sectional view, the shortest distance between the first inner surface 521c of the first portion 521 and the third inner surface 531c of the third portion 531 of the second electrode 53 corresponds to the third distance W3.

[0049] Since the third distance W3 is greater than the second distance W2, the distance in the first direction X between the first inner surface 521c of the first portion 521 and the first surface 13 can be increased. This reduces the possibility that the first joining member 30 will wet and spread towards the second conductive member 20 and reach the first surface 13 of the first conductive member 10. As a result, the possibility of the first joining member 30 coming into contact with the second conductive member 20 and short-circuiting can be reduced. Furthermore, since the area in contact between the covering member 60 and the upper surface of the first conductive member 10 is increased, the adhesion between the covering member 60 and the first conductive member 10 can be improved.

[0050] The outer surface 521d is located opposite the first inner surface 521c in the first direction X. The outer surface 521d corresponds to the side of the first electrode 52 that is furthest to the -X side. In the example shown in Figure 2, the outer surface 521d is a vertical surface perpendicular to the bottom surface 521b of the first portion 521. However, the outer surface 521d may be, for example, an inclined surface that is inclined with respect to the bottom surface 521b of the first portion 521. The inclined surface may be a straight line or a curve in cross-sectional view.

[0051] In the example shown in Figure 2, the second portion 522 has an upper surface 522a that is in contact with the light-emitting portion 51, a lower surface 522b located on the opposite side of the upper surface 522a in the third direction Z, and a second inner surface 522c located between the upper surface 522a and the lower surface 522b in the third direction Z.

[0052] In the example shown in Figure 2, the upper surface 522a and lower surface 522b of the second portion 522 are flat surfaces parallel to the first direction X and the second direction Y. The second inner surface 522c corresponds to the surface of the first electrode 52 that is furthest to the +X side. In the example shown in Figure 2, the second inner surface 522c is a vertical surface perpendicular to the upper surface 522a of the second portion 522. However, the second inner surface 522c may be, for example, an inclined surface that is inclined with respect to the upper surface 522a of the second portion 522.

[0053] In the example shown in Figure 5, in a cross-sectional view, the thickness 522H of the second portion 522 is greater than the thickness 51H of the light-emitting portion 51. However, the thickness 522H of the second portion 522 of the first electrode 52 may be less than or equal to the thickness 51H of the light-emitting portion 51.

[0054] The thickness 522H of the second portion 522 is preferably 0.2 times or more and 0.9 times or less of the thickness 521H of the first portion 521. When the thickness 522H of the second portion 522 is 0.2 times or more of the thickness 521H of the first portion 521, the heat dissipation effect of the second portion 522 on the first electrode 52 is more easily obtained. Also, when the thickness 522H of the second portion 522 is 0.9 times or less of the thickness 521H of the first portion 521, the possibility of the first bonding member 30 reaching the second electrode 53 and / or the second conductive member 20 via the second portion 522 can be reduced. This reduces the possibility of the first bonding member 30 coming into contact with the second electrode 53 and / or the second conductive member 20 and causing a short circuit. Furthermore, the thickness 522H of the second portion 522 is more preferably 0.3 times or more and 0.8 times or less the thickness 521H of the first portion 521, and even more preferably 0.4 times or more and 0.7 times or less the thickness 521H of the first portion 521. This further improves the effect of the second portion 522 on improving the heat dissipation of the first electrode 52, and the effect of reducing the possibility of the first bonding member 30 coming into contact with the second electrode 53 and / or the second conductive member 20 and causing a short circuit.

[0055] Examples of materials constituting the first part 521 and the second part 522 include the metals and alloys listed as examples of materials constituting the first conductive member 10 and the second conductive member 20.

[0056] As shown in Figure 2, the second electrode 53 may have a third portion 531 that is in contact with the light-emitting portion 51 and the second bonding member 40, and a fourth portion 532 that is located on the first electrode 52 side of the third portion 531 and is in contact with the light-emitting portion 51. Furthermore, the lower surface 532b of the fourth portion 532 may be located above the lower surface 531b of the third portion 531.

[0057] The width of the third portion 531 in the first direction X may be the same as or different from the width of the first portion 521 in the first direction X. Also, in the example shown in Figure 5, the third distance W3 is greater than the second distance W2. Therefore, the distance between the third inner surface 531c and the third surface 23 of the third portion 531 in the first direction X can be increased. That is, the distance between the first inner surface 521c and the third surface 23 of the first portion 521 in the first direction X can be increased, and the distance between the third inner surface 531c and the third surface 23 of the third portion 531 in the first direction X can be increased. As a result, the possibility that the first joining member 30 on the first conductive member 10 will wet and spread toward the second conductive member 20 and reach the first surface 13 is reduced, and the possibility that the second joining member 40 on the second conductive member 20 will wet and spread toward the first conductive member 10 and reach the third surface 23 is reduced. As a result, in the third direction Z, the difference between the thickness of the first bonding member 30 on the first conductive member 10 and the thickness of the second bonding member 40 on the second conductive member 20 is reduced, and the tilt of the light-emitting element 50 with respect to the third direction Z can be reduced. The other configurations of the third part 531 can be the same as the other configurations of the first part 521. Therefore, the description of the other configurations of the third part 531 is omitted.

[0058] The width of the fourth part 532 in the first direction X may be the same as or different from the width of the second part 522 in the first direction X. Other components of the fourth part 532 may be the same as other components of the second part 522. Therefore, a description of other components of the fourth part 532 is omitted.

[0059] The second electrode 53 has a fourth portion 532 located on the first electrode 52 side of the third portion 531, which allows the first distance W1 to be shortened compared to a configuration in which the second electrode 53 does not have a fourth portion 532. This improves the heat dissipation of the light-emitting device 1.

[0060] The first electrode 52 may further have a fifth portion located between the first portion 521 and the second portion 522 in the first direction X. The fifth portion is in contact with the light-emitting portion 51 and has a lower surface located above the lower surface 521b of the first portion 521 and below the lower surface 522b of the second portion 522. When the first electrode 52 has the fifth portion, the fifth portion is not covered by the first joining member 30. Similarly, the second electrode 53 may further have a sixth portion located between the third portion 531 and the fourth portion 532 in the first direction X. The sixth portion may have the same configuration as the fifth portion.

[0061] <Covering member 60> The covering member 60 is light-reflecting. The covering member 60 covers the first conductive member 10, the second conductive member 20, the first joining member 30, the second joining member 40, and the light-emitting element 50 such that the lower surface 12 of the first conductive member 10 and the lower surface 22 of the second conductive member 20 are exposed. By exposing the lower surface 12 of the first conductive member 10 and the lower surface 22 of the second conductive member 20 from the covering member 60, the heat generated in the light-emitting part 51 can be easily dissipated to the outside from the lower surfaces of the first conductive member 10 and the second conductive member 20.

[0062] As shown in Figure 2, the covering member 60 covers the side surface of the light-emitting element 50. This allows light emitted from the side surface of the light-emitting element 50 to be reflected to the upper surface of the light-emitting element 50, thereby improving the light extraction efficiency of the light-emitting device 1. In addition, a portion of the covering member 60 is positioned between the first electrode 52 and the second electrode 53, and between the first conductive member 10 and the second conductive member 20 in a cross-sectional view. This reduces the absorption of light emitted downward from the light-emitting element 50 by the first conductive member 10, the second conductive member 20, the first bonding member 30, and the second bonding member 40. As a result, the light extraction efficiency of the light-emitting device 1 can be improved.

[0063] The covering member 60 can have insulating properties. As shown in Figure 2, the covering member 60 is placed between the first electrode 52 and the second electrode 53, and between the first conductive member 10 and the second conductive member 20. Therefore, the possibility of short circuits occurring between the first electrode 52 and the second electrode 53, and between the first conductive member 10 and the second conductive member 20 can be reduced.

[0064] Examples of materials constituting the coating member 60 include thermosetting resins. Examples of thermosetting resins include epoxy resins, modified epoxy resins, silicone resins, modified silicone resins, acrylate resins, polyester resins (e.g., unsaturated polyester resins), and urethane resins. The coating member 60 may also further contain light-reflecting particles. Examples of light-reflecting particles include inorganic particles such as titanium oxide, silicon oxide, aluminum oxide, zirconium oxide, magnesium oxide, potassium titanate, barium titanate, zinc oxide, silicon nitride, aluminum nitride, boron nitride, calcium carbonate, calcium hydroxide, and calcium silicate.

[0065] <Translucent member 70> The light-transmitting member 70 is placed on the light-emitting element 50 and is a light-transmitting member that transmits light emitted from the light-emitting element 50 and emits it to the outside. The light-transmitting member 70 is covered by the covering member 60 so that the upper surface of the light-transmitting member 70 is exposed. Of the light emitted from the light-emitting element 50, the light that passes through the side of the light-transmitting member 70 is reflected by the covering member 60 to the upper surface of the light-transmitting member 70.

[0066] The light-transmitting member 70 may include a wavelength conversion material capable of wavelength conversion of at least a portion of the light from the light-emitting element 50. This facilitates chromaticity adjustment of the light-emitting device 1. The wavelength conversion material included in the light-transmitting member 70 may be of one type or multiple types. The light-transmitting member 70 may consist of a wavelength conversion material and a base material, or it may consist of the wavelength conversion material alone. When the light-transmitting member 70 consists of a wavelength conversion material and a base material, the wavelength conversion material may be included in the base material or placed on the surface of the base material. When the wavelength conversion material is placed on the surface of the base material, the wavelength conversion material can be placed on the surface of the base material facing the light-emitting element 50. Alternatively, only the wavelength conversion material may be placed on the surface of the base material, or a resin containing the wavelength conversion material may be placed thereon. A phosphor can be used as the wavelength conversion material.

[0067] Examples of materials for the base material of the light-transmitting member 70 include inorganic materials such as glass, ceramics, and sapphire, and organic materials such as resins or hybrid resins containing one or more of the following: silicone resin, modified silicone resin, epoxy resin, modified epoxy resin, acrylic resin, phenolic resin, and fluororesin.

[0068] As a phosphor, a yttrium aluminum garnet-based phosphor (e.g., Y3(Al,Ga)5O 12 Ce), lutetium-aluminum-garnet phosphors (e.g., Lu3(Al,Ga)5O 12 Ce), terbium aluminum garnet phosphors (e.g., Tb3(Al,Ga)5O 12 :Ce), CCA-based phosphors (e.g., Ca 10 (PO4)6Cl2:Eu), SAE-based phosphors (e.g., Sr4Al14 O 25 :(Eu), chlorosilicate phosphors (e.g., Ca8MgSi4O 16 Cl2:Eu), β-sialon phosphors (e.g., (Si,Al)3(O,N)4:Eu), α-sialon phosphors (e.g., Ca(Si,Al) 12 (O,N) 16 :Eu), SLA phosphors (e.g., SrLiAl3N4:Eu), CASN phosphors (e.g., CaAlSiN3:Eu) or SCASN phosphors (e.g., (Sr,Ca)AlSiN3:Eu) and other nitride phosphors, KSF phosphors (e.g., K2SiF6:Mn), KSAF phosphors (e.g., K2(Si,Al)F6:Mn) or MGF phosphors (e.g., 3.5MgO·0.5MgF2·GeO2:Mn) and other fluoride phosphors, phosphors having a perovskite structure (e.g., CsPb(F,Cl,Br,I)3), or quantum dot phosphors (e.g., CdSe, InP, AgInS2 or AgInSe2) can be used.

[0069] The light-transmissive member 70 can contain a light-scattering agent. Examples of materials constituting the light-scattering agent include titanium oxide, silicon oxide, aluminum oxide, zinc oxide, magnesium oxide, zirconium oxide, yttrium oxide, calcium fluoride, magnesium fluoride, niobium pentoxide, barium titanate, tantalum pentoxide, barium sulfate, and glass.

[0070] Note that the light-emitting device 1 is not limited to including the light-transmissive member 70 and may not include the light-transmissive member 70.

[0071] <Light guide member 80> The light guide member 80 is a member for joining the light-emitting element 50 and the light-transmitting member 70. The light guide member 80 is positioned between the upper surface of the light-emitting element 50 and the lower surface of the light-transmitting member 70. The light guide member 80 further covers the side surface of the light-emitting section 51. This allows the light guide member 80 to guide the light emitted from the side surface of the light-emitting element 50 to the light-transmitting member 70. As a result, the light extraction efficiency of the light-emitting device 1 can be improved. Note that the light guide member 80 does not necessarily have to cover the side surface of the light-emitting section 51.

[0072] In the example shown in Figure 2, the light guide member has a triangular cross-sectional shape in which the width in the first direction X widens as it extends upward. That is, the outer surface of the light guide member 80 is a straight line in cross-sectional view. However, the outer surface of the light guide member 80 may be curved in cross-sectional view.

[0073] For example, a resin material can be used as the light guide member 80. As the resin material, a resin or hybrid resin containing one or more of the following can be used: silicone resin, modified silicone resin, epoxy resin, modified epoxy resin, acrylic resin, fluororesin, etc.

[0074] In the light-emitting device 1, the light-transmitting member 70 is joined to the light-emitting element 50 via the light-guiding member 80. However, the light-transmitting member 70 may be directly joined to the light-emitting element 50 without the light-guiding member 80. When the light-transmitting member 70 is directly joined to the light-emitting element 50, direct joining methods such as crimping, sintering, surface activation bonding, atomic diffusion bonding, and hydroxyl group bonding can be used.

[0075] [Differentiation] Next, an example of the configuration of the light-emitting device 1A according to a modified embodiment will be described with reference to Figures 6 and 7. Figure 6 is a schematic top view showing the light-emitting device 1A according to the modified embodiment. Figure 7 is a schematic cross-sectional view showing the light-emitting device 1A along the line VII-VII shown in Figure 6. In the modified embodiment, the same reference numerals are used for components similar to those in the embodiment, and their descriptions are omitted as appropriate.

[0076] As shown in Figure 6, the light-emitting device 1A may further include a protection element 90. The protection element 90 and the light-emitting element 50 are connected in parallel. This reduces the voltage load applied between the first electrode 52 and the second electrode 53 of the light-emitting element 50 when an excessive voltage load is applied to the light-emitting element 50 by reducing the resistance of the parallel circuit including the protection element 90 and bypassing the current. In the examples shown in Figures 6 and 7, the protection element 90 is a Zener diode. However, the protection element 90 is not limited to a Zener diode and may be other protection elements such as a varistor.

[0077] In the example shown in Figure 7, the protective element 90 has an element portion 91 and electrodes 92a and 92b with different polarities. Also, in the examples shown in Figures 6 and 7, the protective element 90 straddles the first conductive member 10 and the second conductive member 20. The electrodes 92a and 92b are located on the lower surface of the element portion 91. Electrode 92a is bonded to the first conductive member 10 via a bonding member 95a. Electrode 92b is bonded to the second conductive member 20 via a bonding member 95b. However, electrodes 92a and 92b may be located on the upper surface of the element portion 91. In this case, the protective element 90 is located on one of the first conductive member 10 and the second conductive member 20. Also, electrode 92a is electrically connected to the first conductive member 10, for example, via a bonding wire. Similarly, electrode 92b is electrically connected to the second conductive member 20, for example, via a bonding wire.

[0078] Although preferred embodiments have been described in detail above, the invention is not limited to the embodiments described above, and various modifications and substitutions can be made to the embodiments described above without departing from the scope of the claims.

[0079] The aspects of this disclosure are, for example, as follows: <Item 1> First conductive member and, A second conductive member that is separated from the first conductive member in a first direction, A first bonding member is disposed on the upper surface of the first conductive member, A second bonding member is positioned on the upper surface of the second conductive member, A light-emitting element disposed on the first and second bonding members and spanning the first conductive member and the second conductive member, the light-emitting element having a light-emitting portion and a first electrode and a second electrode disposed on the lower surface of the light-emitting portion and spaced apart from each other in a first direction, A light-reflective covering member covering the first conductive member, the second conductive member, the first bonding member, the second bonding member, and the light-emitting element is provided so that the lower surfaces of the first conductive member and the lower surfaces of the second conductive member are exposed. Equipped with, The first electrode is, The first portion in contact with the light-emitting portion and the first joining member, A second portion located on the second electrode side of the first portion and in contact with the light-emitting portion, the second portion having a lower surface located above the lower surface of the first portion, It has, In a cross-sectional view, The thickness of the second portion of the first electrode is greater than the thickness of the light-emitting portion. The first distance in the first direction between the second portion of the first electrode and the second electrode is smaller than the second distance in the first direction between the first conductive member and the second conductive member. Light-emitting device. <Item 2> The thickness of the second part is 0.2 times or more and 0.9 times or less the thickness of the first part. The light-emitting device described in item 1 above. <Item 3> The first part has a first inner surface located between the lower surface of the first part and the lower surface of the second part, and an outer surface located opposite to the first inner surface, The first joining member covers the lower surface and the outer surface of the first portion, The first inner surface of the first portion and the lower surface of the second portion are exposed from the first joining member. The light-emitting device described in item 1 or item 2 above. <Item 4> The first joining member has an inner portion located between the first portion and the first conductive member, and an outer portion that covers the outer surface of the first portion, The outer portion is in contact with the light-emitting part. The light-emitting device described in item 3 above. <Item 5> The distance in the first direction in the region of the outer portion on the light-emitting part side is the same as the distance in the first direction in the region of the outer portion on the first conductive member side. The light-emitting device described in item 4 above. <Item 6> The distance in the first direction in the region of the outer portion on the light-emitting part side is smaller than the distance in the first direction in the region of the outer portion on the first conductive member side. The light-emitting device described in item 4 above. <Clause 7> The third distance in the first direction between the first inner surface of the first portion and the second electrode is greater than the second distance in the first direction between the first conductive member and the second conductive member. The light-emitting device described in item 3 above. <Item 8> The second electrode has a third portion that is in contact with the light-emitting portion and the second bonding member, and a fourth portion that is located on the first electrode side of the third portion and is in contact with the light-emitting portion, and has a lower surface that is located above the lower surface of the third portion. A light-emitting device according to any one of the above items <1> to <7>. [Explanation of symbols]

[0080] 1.1A Light-emitting device 10 First conductive member 11 Upper surface of the first conductive member 12 Lower surface of the first conductive member 20 Second conductive member 21 Upper surface of the second conductive member 22 Lower surface of the second conductive member 30 First Joining Member 31 Inner part 32,32A outer part 40 Second Joining Member 50 light-emitting elements 51 Light-emitting part 51H Thickness of the light-emitting part 52 1st electrode 521 Part 1 521a Top view of the first part 521b Bottom of first part 521c 1st inner surface 521d External surface 521H Thickness of Part 1 522 Part 2 522a Upper surface of the second part 522b Lower surface of the second part 522c 2nd inner surface 522H Thickness of the second part 53 2nd electrode 531 Part 3 532 Part 4 60 Covering member 70 Translucent material 80 Light guide member 90 protective elements W1 1st distance W2 2nd distance W3 3rd distance

Claims

1. First conductive member and A second conductive member spaced apart from the first conductive member in a first direction, A first bonding member is disposed on the upper surface of the first conductive member, A second bonding member is positioned on the upper surface of the second conductive member, A light-emitting element disposed on the first and second bonding members and spanning the first conductive member and the second conductive member, the light-emitting element having a light-emitting portion and a first electrode and a second electrode disposed on the lower surface of the light-emitting portion and spaced apart from each other in a first direction, A light-reflective covering member covering the first conductive member, the second conductive member, the first bonding member, the second bonding member, and the light-emitting element is provided so that the lower surfaces of the first conductive member and the lower surfaces of the second conductive member are exposed. Equipped with, The first electrode is The first portion in contact with the light-emitting portion and the first joining member, A second portion located on the second electrode side of the first portion and in contact with the light-emitting portion, the second portion having a lower surface located above the lower surface of the first portion, It has, In a cross-sectional view, The thickness of the second portion of the first electrode is greater than the thickness of the light-emitting portion. The first distance in the first direction between the second portion of the first electrode and the second electrode is smaller than the second distance in the first direction between the first conductive member and the second conductive member. Light-emitting device.

2. The thickness of the second portion is 0.2 times or more and 0.9 times or less the thickness of the first portion. The light-emitting device according to claim 1.

3. The first portion has a first inner surface located between the lower surface of the first portion and the lower surface of the second portion, and an outer surface located opposite to the first inner surface, The first joining member covers the lower surface and the outer surface of the first portion, The first inner surface of the first portion and the lower surface of the second portion are exposed from the first joining member. The light-emitting device according to claim 1 or claim 2.

4. The first joining member has an inner portion located between the first portion and the first conductive member, and an outer portion that covers the outer surface of the first portion. The outer portion is in contact with the light-emitting part. The light-emitting device according to claim 3.

5. The distance in the first direction in the region of the outer portion on the light-emitting part side is the same as the distance in the first direction in the region of the outer portion on the first conductive member side. The light-emitting device according to claim 4.

6. The distance in the first direction in the region of the outer portion on the light-emitting portion side is smaller than the distance in the first direction in the region of the outer portion on the first conductive member side. The light-emitting device according to claim 4.

7. The third distance in the first direction between the first inner surface of the first portion and the second electrode is greater than the second distance in the first direction between the first conductive member and the second conductive member. The light-emitting device according to claim 3.

8. The second electrode has a third portion that contacts the light-emitting portion and the second bonding member, and a fourth portion that is located on the first electrode side of the third portion and contacts the light-emitting portion, and has a lower surface that is located above the lower surface of the third portion. The light-emitting device according to claim 1 or claim 2.

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